http://officialfan.proboards.com/index.cgi?board=offtopic&action=display&thread=469581

So, whilst thinking about April Fools day, I got to think about something that I'm sure has been done on a sitcom before.

Basically, the kids are planning an April Fools joke, but the parents overhear them and decide to one-up them with a joke of their own. So, the kids do their April Fools joke, but in the middle of it, the parents get into a huge fight over the kids' joke, thus pranking the kids who didn't know they were in on it.

I want to say that this has happened on Home Improvement or something, but other than that, has this ever happened on a sitcom? I'm sure it has because it's too obvious to never have been done, but I can't think of any examples.

There was at least one Halloween episode of "Home Improvement" where the kids and parents were both trying to outscare each other- perhaps you were thinking of this.
I wouldn't be surprised if this show or some other sitcom did an April Fools' Day type plot though- it'd be a great sitcom episode.

The episode called "I Was A Teenage Taylor" in season 6.